1) Field of the Invention
The present invention relates to tablets featuring good dissolution and absorption of piroxicam and a production process thereof.
2) Description of the Related Art
Piroxicam is a non-steroidal anti-inflammatory agent having excellent antiphlogistic, analgesic and antipyretic effects and is now commercially-available as capsules. It remains at an effective blood concentration when administered only once a day and is therefore a long-acting, excellent therapeutic.
Piroxicam, however, is insoluble in water so that no sufficient absorption is feasible when administered as is. Accordingly, piroxicam is commercially sold in the form of capsules filled with fine-particulate piroxicam ground to several microns to 10 microns or so.
Owing to the inclusion of a compression step by a tableting machine, tablets, on the other hand, are compact compared with capsules even at the same drug content so that the former are more palatable. Accordingly, tablets are often more preferred to capsules, resulting in a strong desire for the development of tablets on piroxicam too.
When tablets are formed by direct compression or wet compression by using piroxicam having the same particle size as that filled in capsules, the tablets so obtained are however accompanied by the drawback that they have poor dissolution and insufficient absorption compared with the capsules.
For the improvement of the dissolution of piroxicam, some methods have been proposed to date, including those using piroxicam as a salt with arginine or lysine (European Patent Publication No. 66458), as a salt with ethylene diamine, monoethanol amine or diethanol amine (European Patent Publication No. 66459) and as a composition with natural albumin (Japanese Patent Laid-Open No. 88522/1990).
However, these methods all relate to injections, ointments and/or creams. No method has yet been found to improve the dissolution and absorption of piroxicam when administered in the form of tablets.